A panel comprising a glass fiber mat bearing an aluminum foil sheet on one side is known for use for heat insulation in the construction and automotive fields. The aluminum foil sheet of this panel serves as a vapor barrier. These panels are used on the exterior of motor vehicles to shield the vehicle floor from the heat that is released by the exhaust system piping. A drawback to this construction is that the glass fiber mat layer is subject to absorption of moisture through its uncoated side, especially when utilized on the underside of a motor vehicle. Additionally, such a panel lacks structural strength and therefore cannot be used as a support, and is also difficult to handle.
In the motor vehicle field, certain characteristics are desirable for an insulating panel. The panel must be shapeable (deformable) so that it can be adapted to the often complex contours of the vehicle parts which are to be insulated. It is often necessary to achieve the lowest possible thermal conductivity and to thermally isolate the insulated structures from adjacent structures. Sound insulation of certain structures is necessary with respect to sound emissions and noise pollution. Due to the stringent requirements of extended product life, high resistance to corrosion is required today, particularly where the product that is subject to corrosion comes into direct contact with moisture and with corrosion-promoting substances (brake dust, road salt, etc.). Finally, during conventional procedures for the bonding of aluminum and a glass fiber mat (which procedures use solvent-containing adhesives), a considerable amount of solvent emission may occur. This is not desirable from the environmental standpoint. Also, it is required that during operation at high temperatures, the quantity of emissions resulting from the decomposition products of heat insulation materials or bonding aids be kept as low as possible.
The Manual "Kunststoffverarbeitung" (Plastic Processing), Vogel-Verlag 1981, page 194, discloses various adhesives for the production of aluminum laminates. Suitable adhesives for glass fiber mat are disclosed on page 142 of this text.
Numerous clamping and gripping devices are known in the art for use in various applications. In the text "Aluminum Taschenbuch" (Aluminum Manual), 14th edition, pp. 827 ff, clamping devices for use with vehicle sheathing, both with and without the use of extruded sections, are disclosed. The devices consist of several separate parts and normally contain a stud or a clamping screw for bracing the fastening elements. It is clearly desirable to minimize the number of clamping devices required to fasten a panel, such as a vehicle sheathing or insulation panel.
For composite panels made with elastic core materials, the known clamping devices designed for use with non-flexible core materials cannot be used. This is especially true for sandwich construction with thin outer layers where a large surface area, for contact between the fastening clamp and the composite panel, is desirable. This large surface area is required to significantly reduce fraying, shattering or tearing of the composite panel in the area of fastening. One problem is that many clamping devices are suitable only for use with panels of a particular thickness, and cannot be easily adapted for use to fasten panels having different thicknesses.